1.只显示地址,不显示内容:
结果显示
@Testpublic void searchUserRole(){List<User>list=userDao.searchUserRole();for(User u:list){System.out.println(u);System.out.println("\t\t"+u.getRoles());}}
查看代码发现没有问题,难道是实体类的原因?
后来发现实体类少了重写ToString()方法:
@Overridepublic String toString() {return "Role{" +"id=" + id +", name='" + name + '\'' +", desc='" + desc + '\'' +", users=" + users +'}';}
但是还是有问题,如下,名字重复:
原因在于user表和role表有字段名重复:
<resultMap id="userRoleMap" type="com.aaa.entity.User"><!--主键字段对应的属性;property:实体类属性;column:数据库列名--><id property="id" column="id"></id><!--非主键字段--><result property="name" column="name"></result><result property="birth" column="birth"></result><result property="gender" column="gender"></result><result property="address" column="address"></result><!--建立了一对多关系之后,需要继续--><collection property="roles" ofType="role"><id property="id" column="id"></id><result property="name" column="name"></result><result property="desc" column="desc"></result></collection></resultMap>
原来的sql语句:
SELECT u.*,r.* FROM user u left JOIN user_role ur on u.id=ur.uid left JOIN role r on ur.rid=r.id
使用别名之后:
<select id="searchUserRole" resultMap="userRoleMap">SELECT u.*,r.id rid,r.name rname,r.descFROM user u left JOIN user_role ur on u.id=ur.uidleft JOIN role r on ur.rid=r.id</select>
再看执行效果:
最终结果正常!